libakgl/include/akgl/iterator.h

/**
 * @file iterator.h
 * @brief The work order handed to a registry sweep.
 *
 * There is no iterator object with a `next()` on it. Traversal is SDL's --
 * `SDL_EnumerateProperties` over a registry -- and this struct is the `userdata`
 * carried into each callback, telling it *which* entries to touch and *what* to
 * do to each one. akgl_registry_iterate_actor and
 * akgl_registry_iterate_character are the callbacks that read it;
 * akgl_game_update, akgl_physics_simulate, and akgl_render_2d_draw_world are the
 * entry points that take one.
 *
 * The operations are independent bits, not an enum: a single sweep can update,
 * scale, and render, and they run in that fixed order regardless of how the bits
 * were set. Passing `NULL` where an `akgl_Iterator *` is expected is not an
 * error at the top-level entry points -- each substitutes its own default set --
 * but it *is* an error once inside a callback.
 */

#ifndef _AKGL_ITERATOR_H_
#define _AKGL_ITERATOR_H_

#include <stdint.h>

/** @brief Selects operations and an optional layer for actor traversal. */
typedef struct {
    uint32_t flags;     /**< Bitwise OR of the `AKGL_ITERATOR_OP_*` values below. */
    uint8_t layerid;    /**< Layer to restrict the sweep to. Read only when #AKGL_ITERATOR_OP_LAYERMASK is set. */
} akgl_Iterator;

#define AKGL_ITERATOR_OP_UPDATE                (1 << 0)             // 1    Call the actor's updatefunc
#define AKGL_ITERATOR_OP_RENDER                (1 << 1)             // 2    Call the actor's renderfunc
#define AKGL_ITERATOR_OP_RELEASE               (1 << 2)             // 4    Release the object back to its heap layer
#define AKGL_ITERATOR_OP_LAYERMASK             (1 << 3)             // 8    Skip anything whose layer != layerid
#define AKGL_ITERATOR_OP_TILEMAPSCALE          (1 << 4)             // 16   Scale actors to the tilemap; otherwise force scale 1.0
#define AKGL_ITERATOR_OP_UNDEFINED_5           (1 << 5)             // 32
#define AKGL_ITERATOR_OP_UNDEFINED_6           (1 << 6)             // 64
#define AKGL_ITERATOR_OP_UNDEFINED_7           (1 << 7)             // 128
#define AKGL_ITERATOR_OP_UNDEFINED_8           (1 << 8)             // 256
#define AKGL_ITERATOR_OP_UNDEFINED_9           (1 << 9)             // 512
#define AKGL_ITERATOR_OP_UNDEFINED_10          (1 << 10)            // 1024
#define AKGL_ITERATOR_OP_UNDEFINED_11          (1 << 11)            // 2048
#define AKGL_ITERATOR_OP_UNDEFINED_12          (1 << 12)            // 4096
#define AKGL_ITERATOR_OP_UNDEFINED_13          (1 << 13)            // 8192
#define AKGL_ITERATOR_OP_UNDEFINED_14          (1 << 14)            // 16384
#define AKGL_ITERATOR_OP_UNDEFINED_15          (1 << 15)            // 32768
#define AKGL_ITERATOR_OP_UNDEFINED_16          (1 << 16)            // 65536
#define AKGL_ITERATOR_OP_UNDEFINED_17          (1 << 17)            // 131072
#define AKGL_ITERATOR_OP_UNDEFINED_18          (1 << 18)            // 262144
#define AKGL_ITERATOR_OP_UNDEFINED_19          (1 << 19)            // 524288
#define AKGL_ITERATOR_OP_UNDEFINED_20          (1 << 20)            // 1048576
#define AKGL_ITERATOR_OP_UNDEFINED_21          (1 << 21)            // 2097152
#define AKGL_ITERATOR_OP_UNDEFINED_22          (1 << 22)            // 4194304
#define AKGL_ITERATOR_OP_UNDEFINED_23          (1 << 23)            // 8388608
#define AKGL_ITERATOR_OP_UNDEFINED_24          (1 << 24)            // 16777216
#define AKGL_ITERATOR_OP_UNDEFINED_25          (1 << 25)            // 33554432
#define AKGL_ITERATOR_OP_UNDEFINED_26          (1 << 26)            // 67108864
#define AKGL_ITERATOR_OP_UNDEFINED_27          (1 << 27)            // 134217728
#define AKGL_ITERATOR_OP_UNDEFINED_28          (1 << 28)            // 268435456
#define AKGL_ITERATOR_OP_UNDEFINED_29          (1 << 29)            // 536870912
#define AKGL_ITERATOR_OP_UNDEFINED_30          (1 << 30)            // 1073741824
#define AKGL_ITERATOR_OP_UNDEFINED_31          (1 << 31)            // 2147483648


#endif // _AKGL_ITERATOR_H_